Breaking the Thermal Bridge

This R-30 wall is inexpensive and easy to build.

Sign up for eletters today and get the latest how-to from Fine Homebuilding, plus special offers.

Longtime builder Stephen Bonfiglioli describes how he builds an R-30 wall using polystyrene strips on the interior of the studs as a thermal break. The method is less expensive and easier to build than wall systems with similar R-values. Bonfiglioli explains how his wall system is constructed, and he gives details for the installation of electrical boxes and the whole-wall vapor retarder he includes as part of the wall system. He also discusses how he prevents moisture accumulation in the stud cavities.